fwrite和fread文件内容传输的问题

想把一个文件内容传送到另一个文件中
#include

using namespace std;

int main()
{
FILE *pfile1 = NULL;
fopen_s(&pfile1,"F:\TestUpload\TestUpload.txt","r");
char buffer[100];
size_t i =0;

FILE * pfile2 = NULL;
fopen_s(&pfile2,"F:\\rec.txt","a");
size_t j = 0;

while(i=fread(buffer,1,10,pfile1))
{
    fwrite(buffer,strlen(buffer),1,pfile2);
    if(i<10)
    {

        cout << "文件读取完毕" << endl;
        break;
    }

}
cout << buffer << endl;

fclose(pfile1);
fclose(pfile2);

return 0;

}

这么写哪里错了？求解

fopen_s(&pfile1,"F:\TestUpload\TestUpload.txt","r");
=>
fopen("文件路径"， “打开方式”)
fopen("F:\TestUpload\TestUpload.txt","r");

fread也一样，建议先百度一下两个函数的参数